Telegraph system



Aug. 18, 1942. F. H. HANLEY TELEGRAPH SYSTEM Filed April 29, 1 941 I INVENTOR ZEEvnZey M (J. G ATI'QRNEY Patented Aug. 18, 1942 TELEGRAPH SYSTEM Frank Harold Hanley, Butler, N. J., assignor to American Telephone and Telegraph Company, a corporation of New York Application April 29, 1941, Serial No. 390,865

2 Claims.

This invention relates to telegraph systems and more particularly to improved repeater arrangements for use in such systems.

In telegraph systems and particularly in telegraph loop terminal circuits it is often desirable to include a single line repeater whereby each of several stations connected with the loop terminal circuit may communicate with each other. Heretofore signals sent by such a repeater have been of the open and closed type, or a combination of the open and closed type and the polar type. The repeater of this invention is so arranged that it will always send signals of the polar type. This will result in a better mode of transmission of the signals. Other objects and features of the invention will appear more fully from. the detailed description of the invention hereinafter given.

The invention may be more fully understood from the following description together with the accompanying drawing in which is shown a circuit diagram illustrating a preferred form of the invention.

In the drawing are shown four telegraph repeaters R1, R2, R3 and R4 of a type well known in the art. Repeaters R1 and R2 are connected together directly over the telegraph loop terminal circuit I. For a marking condition the armature of the sending relay of repeater R1 will be connected to negative battery of 130 volts and the armature of the sending relay of repeater R2 will be connected to positive battery of 130 volts. In like manner repeaters R3 and R4 are connected together directly over the telegraph loop terminal circuit 2. For a marking condition the armature of the sending relay of repeater R3 will be connected to negative battery of 130 volts and the armature of the sending relay of repeater R4. will be connected to positive battery of 130 volts.

In order to enable the repeaters Rsand A4 to communicate with repeaters R1 and R2 and vice versa, the repeater arrangement R5 of this invention is provided. The repeater R5 includes two relays 3 and 4 for transmitting signals from Rs and'R4 to R1 and R2. It also includes two relays 5 and 6 for transmitting signals from R1 and R2 to R3 and R4. Relays 3 and 4 each have two windings. The operating windings of these relays are included in series in telegraph loop terminal circuit 2. The windings to the left of these operating windings serve as biasing windings and under certain conditions as holding windings. Relays 5 and 6 each have two windings. The operating windings of these relays are included in series in telegraph loop terminal circuit I. The windings to the right of these operating windings serve as biasing windings and under certain conditions as holding windings.

The operation of the arrangements of the invention will now be described in detail. As heretofore pointed out, for a marking condition positive battery of 130 volts will be connected to the armature of the sending relay of repeater R4, and negative battery of 130 volts will be connected to the armature of the sending relay of repeater R3. This will result in a current of 60 mills flowing through the operating windings of relays 3 and 4 in the direction indicated by the arrows. Current will flow through the biasing windings of relays 3 and 4 over the following circuit, from the positive pole of battery 8, armature and contact of relay 6, resistance l I, inductance l2, biasing windings of relays 3 and 4 to ground. Battery 8 will produce 130 volts, and this will result in a current of 30, mills flowing through the biasing windings of relays 3 and 4 in the direction indicated by the arrows. Accordingly, the current of 60 mills in the operating windings of these relays will prevail, and these relays will hold their armatures on their marking contacts as shown. In like manner a current of 60 mills will flow through the operating windings of relays 5 and 6 in the direction indicated in the arrows. Current for the biasing windings of relays 5 and 6 is supplied over the following path from the negative pole of 130 volt battery 1, armature and contact of relay 3, resistance l3, inductance l4, windings of relays 6 and 5 to ground. This will result in a current of 30 mills flowing through the biasing windings of relays 5 and 6 in the direction indicated by the arrows. The reason for a controlling current flow through the biasing windings of relays 3, 4, 5 and 6 in the direction indicated by the arrows will be more clear from the following. Resistanc-es I5 and I6 are of 7,600 ohms. Resistances H and I3 are of 2,400 ohms. Accordingly the current flowing from the positive pole of battery 8 through resistance II will be greater than any current from the negative pole of 130 volt battery 1 flowing through the biasing windings of relays 3 and 4 in the opposite direction. Likewise current flowing from the negative pole of battery I through resistance l3 will be greater than any current from the positive pole of volt battery 8 flowing through the biasing windings of relays 5 and 6 in the opposite direction. If a spacing signal is now received at repeater R13, the armature of the sending relay will be connected to positive battery of 130 Volts. As the armature of the sending relay of repeater R4 is also connected to positiv battery of 130 volts, this will cause the current through the operating windings of relays 3 and 4 to fall to zero. Accordingly the current in the biasing windings of relays 3 and 4 will now take control and will move the armatures of said relays from their marking contacts to their spacing contacts. When the armatur of relay 3 moves to its spacing contact, current will be supplied from the negative pole of battery I, over armature and spacing contact of relay 3, over conductor l8 and telegraph loop terminal circuit l to the windings of the receiving relay at repeater R1. As these windings are connected to negative battery, the current flow through said windings will be reduced to zero, and the armature of the receiving relay at repeater R1 will move to its spacing contact. The operation of relay 4 will cause current from the positive pole of battery 9 to be applied over the spacing contact and armature of relay 4, conductor l1, telegraph loop terminal circuit I to the windings of the receiving relay at repeater R2. As these windings are already connected to positive battery, the current flow through said windings will be reduced to zero and the armature of the receiving relay thereat will be moved to its spacing contact. In this manner the spacing signal from a repeater such as R3 will be relayed by repeater R to the repeaters R1 and R2. It will be noted from the foregoing that when the armatures of relays 3 and 4 are moved to their spacing contacts, a negative voltage of 130 volts will be applied at point 20 and a positive voltage of I39 volts will be applied at point 19. This will result in a current flow of 60 mills through the operating windings of relays 5 and 6 in the direction shown by the arrows, and these relays will continue to maintain their armatures on their marking contacts. In order to maintain the armatures of relays 5 and 6 on their marking contacts when the repeater R5 is repeating signals in the direction just described, the arrangements of the invention provide an added feature of holding the armatures of relays 5 and 6 on their marking contacts. It will be noted that when the armature of relay 3 moved to its spacing contact the previously traced circuit from negative battery I through the biasing windings of relays 5 and 6 was broken. Current will now flow from the positive pole of battery 8, through the high resistance l5 and through the biasing windings of relays 5 and 6 to ground. The current flow from battery 8 will be in a reverse direction from the current flow previously produced by a connection to battery 1. The current flow from battery 8 through the biasing windings of these relays will accordingly be in the reverse direction indicated by the arrows and will aid the operating windings to hold their armatures against their marking contacts. In a similar manner when a spacing signal is received either at repeater R1 or R2, the current flow through the operating windings of relays 5 and 6 will be reduced to zero and the current through the biasing windings will cause the armatures of said relays to move to their spacing contacts. When the armature of relay 5 is moved to its spacing contact, negative current from battery 10 will be applied from the spacing contact and armature of relay 5 over conductor 2| to the windings of the receiving relay of repeater R3. This will cause the armature of this receiving relay to move to its spacing contact. When the armature of relay 6 moves to its spacing contact, positive current from battery 8 will be applied over the armature and spacing contact of relay 6, over conductor 22 to the windings of the receiving relay R4. This will cause the armature of said receiving relay to move to its spacing contact. However, this will result in a positive potential of 130 volts being applied at point 23, and a negative potential of 130 volts being applied at point 24. This will result in a current fiow of 60 mills through the operating windings of relays 3 and 4 in a direction indicated by the arrows. Hence the operating windings of these relays will tend to maintain their armatures on their marking contacts. When relay 6 operates and moves its armature to its spacing contact,

the previously traced circuit for the biasing current through low resistance II and the biasing windings of relays 3 and 4 will be broken. Current flowing from the negative pole of battery I and through the high resistance [6 will now flow through the biasing windings of relays 3 and 4 in a direction the reverse of that indicated by the arrows. Current flow in this direction from these biasing windings would tend to aid the current fiow in the operating windings to maintain the armatures of relays 3 and 4 on their marking contacts.

While the invention has been disclosed as embodied in certain specific forms which have been deemed desirable, it is understood that it is capable of embodiment in many and other widely varied forms without departing from the spirit of the invention as defined by the appended claims.

What is claimed is:

1. A first telegraph loop terminal circuit having two repeaters connected thereto, a second telegraph p terminal circuit having two repeaters connected thereto and a repeater interconnecting said circuits, said last-mentioned repeater comprising a first set of relays having operating windings in one of said loop terminal circuits and a biasing Winding for each of said relays, a second set of relays having operating windings in the other of said loop terminal circuits and biasing windings for each of said relays, and means controlled by the operation of either of said sets of relays for repeating a polar signal from one of said loop terminal circuits to the other and for changing the direction of current fiow in the biasing windings of the other set of relays.

2. A first telegraph loop terminal circuit having two repeaters connected thereto, a second telegraph loop terminal circuit having two repeaters connected thereto, a repeater interconnecting said circuits, said last mentioned repeater comprising a first set of two relays having operating windings in one of said loop terminal circuits, a second set of two relays having operating windings in the other of said loop terminal circuits, means controlled by the operation of either of said sets of relays for repeating a polar signal from one of said loop terminal circuits to the other, biasing windings for each of said sets of relays, the biasing windings of one of said sets of relays being connected through a relatively low resistance to the negative pole of a battery connected to a contact of one of the relays of said second set of relays and also being connected through a relatively high resistance to the positive pole of a similar battery whereby when the relays of said second set operate the direction of efiective current flow in said biasing windings will be reversed.

FRANK HAROLD HA NLV EY. 

